$77.2 \times 0.272 = $
${7}$ ${7}$ ${2}$ ${0}$ ${2}$ ${7}$ ${2}$ ${\times\vphantom{0}}$ ${.}$ ${.}$ ${0.2}\times {0.002}= {0.0004}$ ${4}$ ${7}\times {0.002}= {0.014}$ ${4}$ ${70}\times {0.002}+C{0.01}= {0.15}$ ${5}$ ${1}$ ${0.2}\times {0.07}= {0.014}$ ${4}$ ${0}$ ${7}\times {0.07}+C{0.01}= {0.50}$ ${0}$ ${70}\times {0.07}+C{0.5}= {5.4}$ ${4}$ ${5}$ ${0.2}\times {0.2}= {0.04}$ ${4}$ ${0}$ ${0}$ ${7}\times {0.2}= {1.4}$ ${4}$ ${70}\times {0.2}+C{1}= {15}$ ${5}$ ${1}$ ${+\vphantom{0}}$ ${2}$ ${0}$ ${9}$ ${9}$ ${8}$ ${4}$ ${+\vphantom{0}}$ ${2}$ ${0}$ ${9}$ ${9}$ ${8}$ ${4}$ ${.}$ The top number has $1$ digit to the right of the decimal. The bottom number has $3$ digits to the right of the decimal. The product has $1+3=4$ digits to the right of the decimal. $77.2 \times 0.272 = 20.9984$